The disclosure relates to a new type of lens for eyeglasses and a method for obtaining the same.
The technical field is that of lenses for eyeglasses, whether they are sunglasses or corrective eyeglasses. The term “eyeglasses” includes any device designed to protect the wearer's eyes and/or improve his or her vision.
In embodiments, the lenses have a metallic appearance to the observer looking at these lenses. For example, this metallic appearance may be that of a precious metal, such as gold. “Metallic appearance” in the present specification is understood to include lenses that give the observer the appearance of a precious metal present in the form of a layer in said lenses.
The first goal of embodiments is not protection of the user, and the eyeglasses as defined above are not, basically, designed to protect the user from radiation, such as infrared rays, even though, secondarily, the eyeglasses according to embodiments do offer some degree of protection.
Among the known devices designed to protect the user, one may cite a firefighter mask whose visor is coated with a layer of gold, resistant to high temperatures and thus protecting the firefighter from the strong radiation present at fires. Similar masks, namely those whose visor is coated with a gold layer to protect the user from harmful radiation, are also used by astronauts or spacionauts when they take space walks, or by fighter pilots.
In addition, in the case of the aforementioned masks, the relatively large thickness of the gold layer confers on the lens on which this layer is deposited a high degree of reflection on the side of the lens facing the user; this degree of reflection is not troublesome to the aforementioned professionals because the mask is enveloping, thus considerably limiting the light that may be reflected on the inside of the mask, namely the side facing the wearer of this mask.
The problem of troublesome reflection for the user in the case of eyeglasses has been partly solved by French Patent 2,003,177. In this patent, a layer of metal, such as gold, is sandwiched between two transparent layers, and a metal film is disposed in order to reduce the degree of reflection toward the user. The goal of the lens described in this patent is indeed to filter out radiation with infrared and ultraviolet wavelengths that are harmful to the human eye. However, the rendition of the metallic appearance of the lens according to this disclosure, where the gold layer is sandwiched between two transparent layers, is unsatisfactory, as the metallic appearance of the gold layer may be altered.